Flame retardation of textiles using aromatic bromine-containing formulations adhered to the substrates by means of binders, has been long established (for instance, U.S. Pat. No. 3,955,032 and U.S. Pat. No. 4,600,606). The main drawbacks of existing formulations include high bromine content demand, high dry add-on demand, streak marks on dark fabrics, excessive dripping during combustion of thermoplastic fibers and dispersion instability. Most of these drawbacks are inherent to the aromatic bromine compounds used.
Using existing aromatic bromine containing formulations, the percentage resin component may be as high as 60-70 wt % of the total add-on in order to obtain satisfactory flame retardation (see Toxicological Risks of Selected Flame-Retardant Chemicals (2000), by Donald E. Gardner (Chair) Subcommittee on Flame-Retardant Chemicals, Committee on Toxicology, Board on Environmental Studies and Toxicology, National Research Council page 507). This high add-on is due in part to the large amount of binder needed to fix the flame retardant (FR) agents to the textile. The binder may be as high as 50 wt % of the total FR formulation (see Toxicological Risks of Selected Flame-Retardant Chemicals (2000) page 507). Due to its substantial presence, the binder contributes to flammability and dripping, which requires more bromine content, thus creating an inefficient cycle. In order to obtain flame retarded textiles with better performance and less detriment to textile properties, an efficient FR agent conducive to incorporation in low binder content formulations with good dispersion properties is required.
Tris(tribromophenoxy)-s-triazine (FR-245) is a flame retardant with a combination of aromatic bromine and cyanurate that provides high FR efficiency and good thermal stability. In its non-micronized form it is useful in many applications, especially but not exclusively, in the field of fire retardants for plastic compositions. FR-245 is insoluble in water but has a specific gravity of about 2.4, significantly lower than bromine rich FR agents commonly used in such applications such as Decabromodiphenyl Oxide (Deca), which has a specific gravity of 3. FR-245 is also easily micronized. Therefore, FR-245 lends itself to the preparation and use of more stable aqueous dispersions. FR-245 also has a higher initial decomposition temperature than Decabromodiphenyl oxide.
Tetrabromobisphenol A bis(2,3-dibromopropyl ether) (FR-720) is a flame retardant with a combination of aromatic and aliphatic bromine that provides high FR efficiency and good thermal stability. FR-720 is useful in many applications, especially but not exclusively, in the field of fire retardants for plastic compositions. FR-720 is insoluble in water but has a specific gravity of about 2.3, significantly lower than bromine rich FR agents commonly used in such applications such as Decabromodiphenyl Oxide (Deca). FR-720 has an advantage in that a homogenous film can be achieved during the application due to its low melting range (113-117° C.) which enables melt penetration of the material being processed.
It has now been surprisingly found, and this is an object of the present invention, that two specific aromatic flame-retardants, never tested before in textile, possess unexpected stability and compatibility properties, which render them highly efficient for the purpose of flame-retarding textile materials.
It is thus a purpose of this invention to provide stable dispersions or suspensions of A) tris(tribromophenoxy)-s-triazine or B) tetrabromobisphenol A bis(2,3-dibromopropyl ether), or of mixtures thereof, which alleviate the drawbacks of existing formulations for treating textile materials.
It is another purpose of this invention to provide such dispersions or suspensions that are aqueous dispersions or suspensions and which do not require non-aqueous solvents.
It is a further purpose of this invention to provide a process for preparing such aqueous dispersions or suspensions.
It is yet another purpose of the invention to provide dispersions of tris(tribromophenoxy)-s-triazine or tetrabromobisphenol A bis(2,3-dibromopropyl ether) or of a blend of tris(tribromophenoxy)-s-triazine and tetrabromobisphenol A bis(2,3-dibromopropyl ether) for particular uses in the textile industry by coating and/or padding and/or foaming and/or spraying application.
It is still a further purpose of the invention to provide dispersions of tris(tribromophenoxy)-s-triazine or tetrabromobisphenol A bis(2,3-dibromopropyl ether) or a blend of tris(tribromophenoxy)-s-triazine and tetrabromobisphenol A bis(2,3-dibromopropyl ether) together with additional compounds, such as synergists for increasing the fire-retarding efficiency of compositions obtained from these flame retardants.
It is still another purpose of the invention to provide dispersions of tris(tribromophenoxy)-s-triazine or tetrabromobisphenol A bis(2,3-dibromopropyl ether) or a blend of tris(tribromophenoxy)-s-triazine and tetrabromobisphenol A bis(2,3-dibromopropyl ether) with significantly reduced amounts of binder content.
It is also a purpose of the invention to produce a smooth, translucent coating of tris(tribromophenoxy)-s-triazine or tetrabromobisphenol A bis(2,3-dibromopropyl ether) or a blend of tris(tribromophenoxy)-s-triazine and tetrabromobisphenol A bis(2,3-dibromopropyl ether) on textile materials, when applied in aqueous solution.
Other purposes and advantages of the invention will become apparent as the description proceeds.